I. Field of the Invention
The present invention is directed generally to covers or lids for microwave cooking vessels and, more particularly, an universal microwave permeable cover designed to accommodate varying sized open-top vessels and which is provided with an array of openings designed to uniformly vent gases and vapors built up when food is heated in the vessel.
II. Description of the Related Art
The number of microwave ovens in use by the general public has grown at a very high rate. The speed, ease and convenience of preparing foods in microwave ovens has created an increased demand for foods designed specifically to be cooked in microwave ovens and, in addition, for specialty cooking vessels designed to be used to prepare foods in microwave ovens. In general, cooking vessels specifically designed and configured for use in microwave ovens tend to be rather expensive and specialized or limited with respect to use. Such devices include, for example, microwave popcorn poppers illustrated and described in U.S. Pat. No. 4 873 406 to Connor, pressure cookers for microwave ovens, illustrated in U.S. Pat. No. 4 796 777 to Dalquist, et al. and other such containers as are illustrated in Sugisawa, et al., 4 703 149. Many microwave heating packages have been designed with a variety of vent holes and Daniels, 4 745 249, Levendusky, et al., 4 560 850, and Pawlowski, 4 896 009, are illustrative of vessels and packages of a given size which may have one or more vapor permeable vent openings designed for the escape of vapors, the permeation of microwaves, or the like.
While all of these uniquely designed cooking vessels have advanced the art of microwave cooking and provide a convenience to the user, each individual device is typically comparatively expensive; and in order to have a relatively complete set of microwave cooking vessels to meet a variety of cooking needs, the consumer has to invest a significant amount of money to obtain an array of vessel types, each being of relatively limited versatility. Accordingly, most consumers simply utilize open-topped vessels such as casserole dishes, various types of bowls and the like which are compatible with use in microwave ovens and already in their possession to accomplish most microwave cooking and heating. Often transparent polymer film coverings are placed or wrapped over the vessels to provide an inexpensive top seal to retain moisture. However, upon removal of the polymer film, a great deal of steam is often expelled in the user's face and this may lead to steam burns or may even result in the user dropping the dish he has just removed from the microwave oven. Moreover, such coverings can be used but once. The alternative is to leave the dish uncovered, but this leads to undesirable dehydration of the contents and possibly the loss of food into the oven from the container due to steam expansion upon heating by microwaves. If one attempts to provide vent holes in the film, the film often tears and thereby frustrates these efforts.